This invention concerns a process for spinning and cooling spin-oriented multifilaments by means of a spinning apparatus having spinning heads containing spinnerets and cooling shafts with an air-permeable wall through which a stream of air is sucked into the interior of the cooling shaft solely by the frictional entrainment of air by the filaments.
Multifilament continuous filaments of synthetic polymers are produced from a melt at the spinning temperature by means of a spinning device. The melt is forced through boreholes in a spinneret. The resulting melt streams are then cooled and combined to form a filament bundle, which is treated with a spin finish oil, then drawn off with a fiber draw-off device and finally wound onto tubes to form a bobbin.
Cooling is especially important here. The uniformity of cooling has a direct influence on the physical characteristics of the filaments such as uniformity of the Uster-value or dyeing receptivity. Trouble is caused by nonlaminar or turbulent flow of the cooling air. Before the melt streams which arc extruded at a high spinning temperature have cooled below the solidification point, contact with each other or with the thread guides have to be avoided because they would stick.